During the second year of the project, we will continue to collect samples of adipose tissue of infants and young children undergoing elective hernia repair. Photomicrographs of the subjects' fat cells will be measured so as to provide an estimate of the distribution of cell sizes. Anthropometric and sociodemographic data will also be collected at the intake examination. All subjects under 12 months of age will be entered into the longitudinal component. They will be visited in their homes at 12 and 30 months of age, where additional growth measurements and measurements of body composition will be made. In addition, we will collect equivalent data on parents and siblings. At 6 and 18 months, home visits will also be made by a nutritionist who will collect data on dietary intake and feeding patterns, as well as additional measurements of physical growth.